MrLapLap is travelling midweek rom Ravensburg to Schaffhausen which involves a transfer at Friedrichshafen.

It’s only a 4 minute connection time and seems to involve getting from platform 2 to platform 4 (probably involving stairs/elevators)
Specifically it’s the RB87571 that leaves 12:19 and arrives at 12:41 to the IC3056 which leaves Friedrichshafen at 12:45

I saw there is a train that gets to Schaffhausen earlier (12:12 – 12:25 from Ravensburg) and arrives at platform 3 (shared with platform 4, so just a few steps). He will have 23kg of luggage/tools.

He already has a ticket (bought with Trip.com, his eventual destination is ZRH) so the question is if he can use a rail journey ticket on this earlier train or whether to get a 5-6Euro ticket for this portion of the journey.
Also, if it’s necessary to get the extra ticket, should he put both tickets through the gate at Ravensburg (I wonder if by not “starting’ his ticket it might invalidate it)